ruːl əv θʌm
General
neutral
beginner
- Literally:
- A rule based on the thumb measurement
What does "rule of thumb" mean?
- A practical principle or guideline
- An approximate method or general principle
Examples
- As a rule of thumb, save 20% of your income.
- My rule of thumb is to arrive 10 minutes early.
- A good rule of thumb for cooking rice is two cups of water per cup of rice.
Origin
Possibly from using the thumb as a rough measuring tool in trades. Brewers checked temperature with their thumb. Dates to the 1600s.
How to use it
Very common in practical advice. Not legally binding, just practical guidance.
Similar expressions
general guideline
rough estimate
practical principle
Opposites
exact rule
precise calculation
Related idioms
- actions speak louder than words
What people do is more important than what they say
- better safe than sorry
It's better to be careful and prevent problems than to take risks
- so far so good
Things have gone well up to now
- easier said than done
Something is more difficult to do than to talk about
- make a long story short
To summarize or get to the point
- to make matters worse
In addition to existing problems
Use it in a practice answer
Try "rule of thumb" in a CELPIP-style Speaking or Writing task. The AI feedback tells you whether your word choice worked.